In gas turbine engines, compressed air discharged from a compressor section and fuel introduced from a source of fuel are mixed together and burned in a combustion section, creating combustion products defining hot working gases. The working gases are directed through a hot gas path in a turbine section, where they expand to provide rotation of a turbine rotor. The turbine rotor may be linked to an electric generator, wherein the rotation of the turbine rotor can be used to produce electricity in the generator.
In view of high pressure ratios and high engine firing temperatures implemented in modern engines, certain components, such as rotating blade structures within the turbine section, must be cooled with cooling fluid, such as compressor discharge air, to prevent overheating of the components. The rotating components associated with the rotor may be moving at a substantially higher speed than the cooling air supplied for cooling the components such that the cooling air may produce a drag force on the rotating components, which may result in reduced output of the engine and an increased temperature of the cooling air.